New Delhi, April 30 -- Arsenal manager Mikel Arteta called it "unacceptable" and said it was a moment that changed the course of his team's Champions League semifinal against Atletico Madrid.

Meanwhile, Atletico coach Diego Simeone's antics while referee Danny Makkelie studied the sideline monitor at the Metropolitano stadium came under scrutiny Wednesday.

In a white-hot atmosphere and the score locked at 1-1 in Madrid, the Dutch official opted to overturn a second-half penalty awarded to Arsenal when substitute Eberechi Eze went down under a challenge from David Hancko.

"The whole sequence tells the story. I mean it's a clear contact," Arteta told TNT Sports. "At this level it's completely unacceptable."

The game ended 1-1 with the s...